Core Practical 13a Post Lab

CPAC 4b - Obtains accurate, precise and sufficient data for experimental and investigative procedures and records this methodically using appropriate units and conventions.

· Write down the exact burette value to 0.05cm³

· Time is recorded to the nearest second

· Data recorded includes units

· average time is recorded, to appropriate accuracy (for time, no more accurate than to a whole second due to human error issues)

CPAC 5a - uses appropriate software and/or tools to process data, carry out research and report findings

• Use excel to draw scatter graph (line of best fit drawn free-hand) to determine the order of reaction with respect to iodine

• Carry out suitable research and writes up in own words citing relevant information, facts and figures within the text as necessary.

Research order with respect to propanone and hydrogen ions

Research potential mechanism to fit orders

CPAC 5b – Sources of information are cited demonstrating that research has taken place, supporting planning and conclusions

· Clearly identifies any material that is a direct quote as such.

· Use research to explain & support any conclusions drawn

· Compile a bibliography of texts from which material has been sourced in such a way that the reader may retrieve the information easily

Calculate a rate of change from a graph showing a linear relationship

The reaction between propanone and iodine in aqueous solution can be catalysed by an acid:

I2(aq) + CH3COCH3(aq) + H+ (aq) → CH3COCH2I(aq) + 2H+ (aq) + I− (aq)

The influence of the iodine on the reaction rate can be studied if the concentrations of propanone and hydrogen ions effectively remain constant during the reaction. This is achieved by using a large excess of both propanone and sulfuric acid in the starting reaction mixture.